In prior practices in the discharge of a stack of hay from a stack maker, the stack maker is constructed so that the floor of the stack maker is only about eighteen to twenty inches from the ground. In the small stack makers the box does not tilt as the box is close enough to the ground. In large stack makers the box is hydraulically tilted upwardly at the forward end so that the back of the box is lowered close to the ground. Discharge of the stack is then accomplished after the box is tilted by the use of a half door or tailgate at the rear of the stack maker with a second half door which requires tilting upwardly or a pair of doors are used and opened laterally at the back of the stack maker. Unloading chains revolving rearwardly in the bed of the box move the stack rearwardly out of the wagon when the doors are opened laterally and when a half door has been used the unloading chains in the box have been aided by unloading chains on the rear half door when the door is sloped to the ground.
The tailgate unloading structure of the present invention employs a single tailgate on the rear of a self-unloading chopper or forage wagon which ordinarily extends above the rear opening of the wagon and when lowered to discharge a load of material from the wagon despite the height of the wagon box from the ground eliminates the necessity of tilting the wagon. The material can be unloaded without damaging such as the forming of cracks in a stack of hay which would subject the stack to injury from the weather.